PLASTIC PAN 

 330>3e II 13 9 CM 

 (13115x550 IN ) 



I 9 CM PLVWOOO 

 (0 75 IN ) 



3 CM PLASTIC CONNECTION (0 12 IN ) 



TUBING CLAMP 



PLASTIC "T" 



Figure 6. — Removable table top and holding pans 

 equipped for continuous water circulation. 



a messenger dropped down the cable. Use of 

 this device is restricted to large vessels equipped 

 with a winch, and requires that the vessel be 

 stopped when shrimp are released. To circum- 

 vent these requirements, we designed an ex- 

 pendable release canister that can be put over- 

 board while a vessel is underway and a release 

 tube for use in shallow water. 



The canister (Fig. 7) is constructed of high- 

 impact styrene plastic formed into a hollow cyl- 

 inder. Tabs on each of the styrene plastic end 

 pieces have holes to accommodate retaining rods 



used in assembling the canister. Assembly and 

 loading are accomplished in a cradle attached 

 to the inner wall of a holding tank so that shrimp 

 will remain submerged until the canister is 

 ready to be put overboard. Slots in the canister 

 allow it to fill with water. 



A salt block, a rubber band, and a paper clip 

 constitute the release mechanism. This mech- 

 anism is set by folding together the two ends of 

 the styrene plastic sheet (thus forming a cyl- 

 inder) and securing them with a rubber band. 

 When ends A and B (see canister. Fig. 7) are 

 folded, the paper clip is inside the canister with 

 the attached rubber band inserted through a 

 hole (end A) and a slot (end B). The salt 

 block is then inserted in the loop formed by 

 the rubber band, and the retaining rods are 

 removed. 



A cement weight (1.1 kg or 2.5 lb.) is attached 

 and the canister is lowered to the water surface 

 and released. When the salt block dissolves, 

 tension in the canister wall pulls the rubber band 

 from the slot (end B) and the canister disas- 

 sembles, releasing the shrimp. Although never 

 obsen-ed during the actual release of shrimp in 

 offshore waters, this release devise was tested 

 in shallow estuarine waters and in the labora- 

 tory. In all tests it performed as expected. The 

 canister accommodates up to 100 shrimp that 



CANISTER ENDS 



r76CM (3IN ) 



r*4^ 



(0 03 IN) 

 -008 CM Thick 



ASSEMBLY OF CANISTER 

 B 



SALT BLOCK, 



06 CM (0 25 IN) ^^ 

 11.4 CM (4 SO IN j 



81.3 CM 



(32 IN) 



CANISTER SIDE 



ASSEMBLED 

 CANISTER 

 WEIGHT 



Figure 7. — Disposable release canister showing release mechanism, loading cradle, and 



method of assembly. 



250 



